（1）although与though可以引导让步状语从句,不能与but连用,但可以与yet连用。

Although they are poor,（yet）they are warm-hearted.

（2）even if或even though引导让步状语从句,表示“即使”,“纵然”,用来使人注意下文所强调内容的性质。

I'll get there even if（though）I have to sell my house to get enough money to go by air.

（3）no matter后接上who、what、where、how等疑问词,也可以在这类疑问词后面加上ever构成whoever、whatever、wherever、however等。

Don't trust him, no matter what/whatever he says.

Whoever breaks the law will be published.

No matter how hard the work is, you'd better try to do it well.

（4）as也可以引导让步状语从句。要用倒装。

Child as（though）he is, he knows a lot.

Much as I like it, I won't buy.

Try as he would, he couldn't lift the heavy box.